(80g) Determination of CO2 Solubility in Brines and Hydrocarbons for Carbon Storage and Enhanced Oil Recovery

The release of CO₂, a major greenhouse gas (GHG), into the atmosphere is predominantly a consequence of excessive fossil fuel usage for industrial and transportation purposes. GHG emissions are known to cause environmental issues such as climate change. CO₂-based enhanced oil recovery (EOR) methods have been considered as a viable option to mitigate atmospheric CO₂ concentrations, due to their potential to permanently sequester a significant fraction of the injected CO₂, via solubility-, capillary-, and stratigraphic- trapping mechanisms, while meeting the growing demand for energy resources. During the CO₂ EOR, some of the injected CO₂ dissolves in the oil and brine phases and impacts the trapping mechanisms. Therefore, it is important to quantify the solubilities of CO₂ in the oil and brine phases.

In this research, we developed two novel experimental setups to measure CO₂ solubility in brines and hydrocarbons. The solubilities of CO₂ in brines of various salinities were measured as a function of pressure (150 psig to 1200 psig) at 65 °F (18 °C). The experimental results were compared with the CO₂ solubility predicted using Duan and Sun (2003) equation of state model. The experimental results are found to be in good agreement with the model predictions. The solubilities of CO₂ in n-hexane, n-decane, n-dodecane and a crude oil were measured at pressures ranging from 150 psig to 700 psig at 18 °C, using a swelling-based procedure. Then, the CO₂ solubilities were estimated using the swelling factors.